Apparatus for grinding cutter bars of mowing machines



9 2 5, 3 4 9 S 7 E 1 N I H C A M G N I w O A. HlRTH Jan. 16, 1934.

APPARATUS FOR GRINDING CUTTER BARS OF M @Vm/27m -Fiklec'l June l5, 1935 Patented `an. 16', 1934 PATENT orifice APPARATUS Fon GRINDING CUTTER BAns oF yMowlrivcf MACHINES Alphense Hirth, Burnhaupt-le-Haut, France Application June 15, 1933, Serial No. 675,987,

l and in France June 20, 1932 6 Claims.

My invention relates to an apparatus for grinding cutter bars of mowing machines, the main feature of which consists in a grinding disc the working surface of which is inclined according to the cutting edge of the tooth to be sharpened, said grinding disc being slidably mounted on its axis, while the cutter bar holder is moving in a direction perpendicular to the disc axis, both motions being combined in such a way that the whole length of the cutting edge is submitted to the same uniform sharpening.

A preferred embodiment of my apparatus comprises two separate grinding discs, which are slidably mounted on a common driving shaft and to which simultaneous sliding motions in opposite directions are imparted, each disc having to grind a cutting edge of the tooth.

In an apparatus of this kind the cutter bar holder may be pivotally mounted on the general frame of the apparatus, so as to permit its displacement perpendicular to the axis of the grinding disc.

Another feature of apparatus of this kind would be the actuating inV common of the displacement of the grinding discs Vand the cutter bar holder, so as the grinding of a tooth is performed by a single movement of a hand lever or the like.

My invention also relates to other features hereinafter described and to their combination.

The accompanying drawing shows by way of example an apparatus according to my invention.

Fig. 1 is an elevation.

Fig. 2 a plan view and Fig. 3 a front View of the apparatus.

A frame 1 mounted on pillars 2 is supporting the grinding discs 31, 32 and the holder 6 for the cutter bar.

The grinding discs 31 and 32 the working surfaces of which are inclined are respectively mounted on sleeves 41, 42 sliding each separately on a common driving shaft 5, the latter supported by bearings forming part of the frame 1.

'Ihe sliding sleeves 41, 42 are rotated by the driving shaft owing tc an elongated key and each comprises an annular groove '71, '72, in which levers 81, 82 jointedly connected at one end to the frame 1 engage. The other ends of the levers are secured by links 111, 112 to a hand lever 12 pivotally mounted on axle 14 of the frame.

The cutter bar holder 6 is a flat iron with ends bent at right angles upwardly; between these ends a shaft 16 is extending and bearing two arms 171 172 which can freely turn and slide on the shaft. On the other hand the flat iron has two projections by which it is jointedly connected to the frame 1. Moreover, a finger 23 on the lever 12 engages a guide member on the fiat iron.

On the ends 181 182 of the arms 1'71 172 clamping devices 201 202 operated by screwing bolts 211 212 are provided for holding the cutter bar 19, the teeth of which are to be grinded. The opposite arm parts are bearing movable counterweights which have to compensate in part the weight of the cutter bar.

The apparatus acts as follows: The discs 31 32 in rotating are each sharpening a cutting edge of a tooth. The inclination of the disc section corresponds to that of the teeth. By actuating the hand lever 12 the grinding discs are moved in two opposite directions on their driving shaft and at the same time the holder 6 is advanced towards said discs, whereby a constant grinding angle is maintained. When by a single or several movements to and fro, the whole length of the cutting edges is sharpened, the cutter bar is pushed sideward so that the next tooth may come into contact with the discs and be sharpened. In the same way all teeth of the cutter bar are ground one after the other. In order to facilitate the actuation of the machine and to equalize the quantities of material taken off on each tooth by the grinding discs adjustable stops may limit the course of the hand lever towards both sides.

It may be well understood, that while I am describing a special embodiment of my invention, I may not limit myself to such devices as shown and described, since what I claim is:

1. An apparatus for grinding cutter bars of mowing machines comprising a frame, a driving shaft, bearings for the shaft on the frame, a grinding disc slidably mounted on the driving shaft and having a working surface inclined according to the cutting edge of the bar teeth, a cutter bar holder moving in a direction perpendicular to the disc axis and mea-ns for effecting in combination the lateral displacement of the grinding disc and the advancing movements of the bar holder.

2. An apparatus for grinding cutter bars of mowing machines comprising a frame, a driving shaft, hearings for the shaft on the frame, two grinding discs slidably mounted on the driving shaft and having working surfaces inclined according to the opposite cutting edges of the bar teeth, a cutter bar holder moving in a direction perpendicular to the disc axis and means for effecting in combination the lateral displacement of the grinding discs and the advancing movement of the bar holder.

3. An apparatus for grinding the cutter bar for mowing machines comprising a frame, a driving shaft, bearings for the shaft on the frame, two grinding discs slidably mounted on the driving shaft and having working surfaces inclined according to the opposite cutting edges of the bar teeth, means for simultaneously moving the grinding discs in opposite directions, a cutter bar holder advancing in a direction perpendicular to the disc axis and means for effecting in combina,- tion the lateral displacement of the grinding discs and the advancing movement of the bar holder.

4. An apparatus for grinding the cutter bar for mowing machines comprising a frame, a driving shaft, bearings for the shaft on the frame, two grinding discs slidably mounted on the driving shaft and having working surfaces inclined according to the opposite cutting edges of the bar teeth, a cutter bar holder advancing in a direction perpendicular` to the disc axis and means for effecting in combination the lateral displacement in opposite directions of the grinding discs and the advancing movement of the bar holder.

5. In apparatus according to claim 1, a cutter bar holder comprising a fiat iron support with upwardly bent ends, a shaft extending between both ends, pivotally and slidably mounted arms on the shaft, clamping devices for holding the cutter bar on the arms,v adjustable counter weights for the cutter bar on the arms and extensions on the at iron support jointedly connected to the frame.

6. In an apparatus according to claim 2, sliding sleeves for the grinding discs, actuating levers jointedly connected to the frame for said sleeves a hand lever pivotally mounted on the frame, links connecting the actuating levers to the hand lever, an upwardly turned finger on the latter and a guide member engaging with the finger on the means for advancing the bar holder.

ALPHONSE HIRTI-I. 

